1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 1991, 1992 Linus Torvalds 4 * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE 5 * Copyright (C) 2016 - 2020 Christoph Hellwig 6 */ 7 #include <linux/init.h> 8 #include <linux/mm.h> 9 #include <linux/blkdev.h> 10 #include <linux/buffer_head.h> 11 #include <linux/mpage.h> 12 #include <linux/uio.h> 13 #include <linux/namei.h> 14 #include <linux/task_io_accounting_ops.h> 15 #include <linux/falloc.h> 16 #include <linux/suspend.h> 17 #include <linux/fs.h> 18 #include <linux/module.h> 19 #include "blk.h" 20 21 static inline struct inode *bdev_file_inode(struct file *file) 22 { 23 return file->f_mapping->host; 24 } 25 26 static int blkdev_get_block(struct inode *inode, sector_t iblock, 27 struct buffer_head *bh, int create) 28 { 29 bh->b_bdev = I_BDEV(inode); 30 bh->b_blocknr = iblock; 31 set_buffer_mapped(bh); 32 return 0; 33 } 34 35 static blk_opf_t dio_bio_write_op(struct kiocb *iocb) 36 { 37 blk_opf_t opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE; 38 39 /* avoid the need for a I/O completion work item */ 40 if (iocb_is_dsync(iocb)) 41 opf |= REQ_FUA; 42 return opf; 43 } 44 45 static bool blkdev_dio_unaligned(struct block_device *bdev, loff_t pos, 46 struct iov_iter *iter) 47 { 48 return pos & (bdev_logical_block_size(bdev) - 1) || 49 !bdev_iter_is_aligned(bdev, iter); 50 } 51 52 #define DIO_INLINE_BIO_VECS 4 53 54 static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb, 55 struct iov_iter *iter, unsigned int nr_pages) 56 { 57 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); 58 struct bio_vec inline_vecs[DIO_INLINE_BIO_VECS], *vecs; 59 loff_t pos = iocb->ki_pos; 60 bool should_dirty = false; 61 struct bio bio; 62 ssize_t ret; 63 64 if (blkdev_dio_unaligned(bdev, pos, iter)) 65 return -EINVAL; 66 67 if (nr_pages <= DIO_INLINE_BIO_VECS) 68 vecs = inline_vecs; 69 else { 70 vecs = kmalloc_array(nr_pages, sizeof(struct bio_vec), 71 GFP_KERNEL); 72 if (!vecs) 73 return -ENOMEM; 74 } 75 76 if (iov_iter_rw(iter) == READ) { 77 bio_init(&bio, bdev, vecs, nr_pages, REQ_OP_READ); 78 if (user_backed_iter(iter)) 79 should_dirty = true; 80 } else { 81 bio_init(&bio, bdev, vecs, nr_pages, dio_bio_write_op(iocb)); 82 } 83 bio.bi_iter.bi_sector = pos >> SECTOR_SHIFT; 84 bio.bi_ioprio = iocb->ki_ioprio; 85 86 ret = bio_iov_iter_get_pages(&bio, iter); 87 if (unlikely(ret)) 88 goto out; 89 ret = bio.bi_iter.bi_size; 90 91 if (iov_iter_rw(iter) == WRITE) 92 task_io_account_write(ret); 93 94 if (iocb->ki_flags & IOCB_NOWAIT) 95 bio.bi_opf |= REQ_NOWAIT; 96 97 submit_bio_wait(&bio); 98 99 bio_release_pages(&bio, should_dirty); 100 if (unlikely(bio.bi_status)) 101 ret = blk_status_to_errno(bio.bi_status); 102 103 out: 104 if (vecs != inline_vecs) 105 kfree(vecs); 106 107 bio_uninit(&bio); 108 109 return ret; 110 } 111 112 enum { 113 DIO_SHOULD_DIRTY = 1, 114 DIO_IS_SYNC = 2, 115 }; 116 117 struct blkdev_dio { 118 union { 119 struct kiocb *iocb; 120 struct task_struct *waiter; 121 }; 122 size_t size; 123 atomic_t ref; 124 unsigned int flags; 125 struct bio bio ____cacheline_aligned_in_smp; 126 }; 127 128 static struct bio_set blkdev_dio_pool; 129 130 static void blkdev_bio_end_io(struct bio *bio) 131 { 132 struct blkdev_dio *dio = bio->bi_private; 133 bool should_dirty = dio->flags & DIO_SHOULD_DIRTY; 134 135 if (bio->bi_status && !dio->bio.bi_status) 136 dio->bio.bi_status = bio->bi_status; 137 138 if (atomic_dec_and_test(&dio->ref)) { 139 if (!(dio->flags & DIO_IS_SYNC)) { 140 struct kiocb *iocb = dio->iocb; 141 ssize_t ret; 142 143 WRITE_ONCE(iocb->private, NULL); 144 145 if (likely(!dio->bio.bi_status)) { 146 ret = dio->size; 147 iocb->ki_pos += ret; 148 } else { 149 ret = blk_status_to_errno(dio->bio.bi_status); 150 } 151 152 dio->iocb->ki_complete(iocb, ret); 153 bio_put(&dio->bio); 154 } else { 155 struct task_struct *waiter = dio->waiter; 156 157 WRITE_ONCE(dio->waiter, NULL); 158 blk_wake_io_task(waiter); 159 } 160 } 161 162 if (should_dirty) { 163 bio_check_pages_dirty(bio); 164 } else { 165 bio_release_pages(bio, false); 166 bio_put(bio); 167 } 168 } 169 170 static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, 171 unsigned int nr_pages) 172 { 173 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); 174 struct blk_plug plug; 175 struct blkdev_dio *dio; 176 struct bio *bio; 177 bool is_read = (iov_iter_rw(iter) == READ), is_sync; 178 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb); 179 loff_t pos = iocb->ki_pos; 180 int ret = 0; 181 182 if (blkdev_dio_unaligned(bdev, pos, iter)) 183 return -EINVAL; 184 185 if (iocb->ki_flags & IOCB_ALLOC_CACHE) 186 opf |= REQ_ALLOC_CACHE; 187 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL, 188 &blkdev_dio_pool); 189 dio = container_of(bio, struct blkdev_dio, bio); 190 atomic_set(&dio->ref, 1); 191 /* 192 * Grab an extra reference to ensure the dio structure which is embedded 193 * into the first bio stays around. 194 */ 195 bio_get(bio); 196 197 is_sync = is_sync_kiocb(iocb); 198 if (is_sync) { 199 dio->flags = DIO_IS_SYNC; 200 dio->waiter = current; 201 } else { 202 dio->flags = 0; 203 dio->iocb = iocb; 204 } 205 206 dio->size = 0; 207 if (is_read && user_backed_iter(iter)) 208 dio->flags |= DIO_SHOULD_DIRTY; 209 210 blk_start_plug(&plug); 211 212 for (;;) { 213 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT; 214 bio->bi_private = dio; 215 bio->bi_end_io = blkdev_bio_end_io; 216 bio->bi_ioprio = iocb->ki_ioprio; 217 218 ret = bio_iov_iter_get_pages(bio, iter); 219 if (unlikely(ret)) { 220 bio->bi_status = BLK_STS_IOERR; 221 bio_endio(bio); 222 break; 223 } 224 if (iocb->ki_flags & IOCB_NOWAIT) { 225 /* 226 * This is nonblocking IO, and we need to allocate 227 * another bio if we have data left to map. As we 228 * cannot guarantee that one of the sub bios will not 229 * fail getting issued FOR NOWAIT and as error results 230 * are coalesced across all of them, be safe and ask for 231 * a retry of this from blocking context. 232 */ 233 if (unlikely(iov_iter_count(iter))) { 234 bio_release_pages(bio, false); 235 bio_clear_flag(bio, BIO_REFFED); 236 bio_put(bio); 237 blk_finish_plug(&plug); 238 return -EAGAIN; 239 } 240 bio->bi_opf |= REQ_NOWAIT; 241 } 242 243 if (is_read) { 244 if (dio->flags & DIO_SHOULD_DIRTY) 245 bio_set_pages_dirty(bio); 246 } else { 247 task_io_account_write(bio->bi_iter.bi_size); 248 } 249 dio->size += bio->bi_iter.bi_size; 250 pos += bio->bi_iter.bi_size; 251 252 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS); 253 if (!nr_pages) { 254 submit_bio(bio); 255 break; 256 } 257 atomic_inc(&dio->ref); 258 submit_bio(bio); 259 bio = bio_alloc(bdev, nr_pages, opf, GFP_KERNEL); 260 } 261 262 blk_finish_plug(&plug); 263 264 if (!is_sync) 265 return -EIOCBQUEUED; 266 267 for (;;) { 268 set_current_state(TASK_UNINTERRUPTIBLE); 269 if (!READ_ONCE(dio->waiter)) 270 break; 271 blk_io_schedule(); 272 } 273 __set_current_state(TASK_RUNNING); 274 275 if (!ret) 276 ret = blk_status_to_errno(dio->bio.bi_status); 277 if (likely(!ret)) 278 ret = dio->size; 279 280 bio_put(&dio->bio); 281 return ret; 282 } 283 284 static void blkdev_bio_end_io_async(struct bio *bio) 285 { 286 struct blkdev_dio *dio = container_of(bio, struct blkdev_dio, bio); 287 struct kiocb *iocb = dio->iocb; 288 ssize_t ret; 289 290 WRITE_ONCE(iocb->private, NULL); 291 292 if (likely(!bio->bi_status)) { 293 ret = dio->size; 294 iocb->ki_pos += ret; 295 } else { 296 ret = blk_status_to_errno(bio->bi_status); 297 } 298 299 iocb->ki_complete(iocb, ret); 300 301 if (dio->flags & DIO_SHOULD_DIRTY) { 302 bio_check_pages_dirty(bio); 303 } else { 304 bio_release_pages(bio, false); 305 bio_put(bio); 306 } 307 } 308 309 static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb, 310 struct iov_iter *iter, 311 unsigned int nr_pages) 312 { 313 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); 314 bool is_read = iov_iter_rw(iter) == READ; 315 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb); 316 struct blkdev_dio *dio; 317 struct bio *bio; 318 loff_t pos = iocb->ki_pos; 319 int ret = 0; 320 321 if (blkdev_dio_unaligned(bdev, pos, iter)) 322 return -EINVAL; 323 324 if (iocb->ki_flags & IOCB_ALLOC_CACHE) 325 opf |= REQ_ALLOC_CACHE; 326 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL, 327 &blkdev_dio_pool); 328 dio = container_of(bio, struct blkdev_dio, bio); 329 dio->flags = 0; 330 dio->iocb = iocb; 331 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT; 332 bio->bi_end_io = blkdev_bio_end_io_async; 333 bio->bi_ioprio = iocb->ki_ioprio; 334 335 if (iov_iter_is_bvec(iter)) { 336 /* 337 * Users don't rely on the iterator being in any particular 338 * state for async I/O returning -EIOCBQUEUED, hence we can 339 * avoid expensive iov_iter_advance(). Bypass 340 * bio_iov_iter_get_pages() and set the bvec directly. 341 */ 342 bio_iov_bvec_set(bio, iter); 343 } else { 344 ret = bio_iov_iter_get_pages(bio, iter); 345 if (unlikely(ret)) { 346 bio_put(bio); 347 return ret; 348 } 349 } 350 dio->size = bio->bi_iter.bi_size; 351 352 if (is_read) { 353 if (user_backed_iter(iter)) { 354 dio->flags |= DIO_SHOULD_DIRTY; 355 bio_set_pages_dirty(bio); 356 } 357 } else { 358 task_io_account_write(bio->bi_iter.bi_size); 359 } 360 361 if (iocb->ki_flags & IOCB_NOWAIT) 362 bio->bi_opf |= REQ_NOWAIT; 363 364 if (iocb->ki_flags & IOCB_HIPRI) { 365 bio->bi_opf |= REQ_POLLED; 366 submit_bio(bio); 367 WRITE_ONCE(iocb->private, bio); 368 } else { 369 submit_bio(bio); 370 } 371 return -EIOCBQUEUED; 372 } 373 374 static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter) 375 { 376 unsigned int nr_pages; 377 378 if (!iov_iter_count(iter)) 379 return 0; 380 381 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1); 382 if (likely(nr_pages <= BIO_MAX_VECS)) { 383 if (is_sync_kiocb(iocb)) 384 return __blkdev_direct_IO_simple(iocb, iter, nr_pages); 385 return __blkdev_direct_IO_async(iocb, iter, nr_pages); 386 } 387 return __blkdev_direct_IO(iocb, iter, bio_max_segs(nr_pages)); 388 } 389 390 static int blkdev_writepage(struct page *page, struct writeback_control *wbc) 391 { 392 return block_write_full_page(page, blkdev_get_block, wbc); 393 } 394 395 static int blkdev_read_folio(struct file *file, struct folio *folio) 396 { 397 return block_read_full_folio(folio, blkdev_get_block); 398 } 399 400 static void blkdev_readahead(struct readahead_control *rac) 401 { 402 mpage_readahead(rac, blkdev_get_block); 403 } 404 405 static int blkdev_write_begin(struct file *file, struct address_space *mapping, 406 loff_t pos, unsigned len, struct page **pagep, void **fsdata) 407 { 408 return block_write_begin(mapping, pos, len, pagep, blkdev_get_block); 409 } 410 411 static int blkdev_write_end(struct file *file, struct address_space *mapping, 412 loff_t pos, unsigned len, unsigned copied, struct page *page, 413 void *fsdata) 414 { 415 int ret; 416 ret = block_write_end(file, mapping, pos, len, copied, page, fsdata); 417 418 unlock_page(page); 419 put_page(page); 420 421 return ret; 422 } 423 424 const struct address_space_operations def_blk_aops = { 425 .dirty_folio = block_dirty_folio, 426 .invalidate_folio = block_invalidate_folio, 427 .read_folio = blkdev_read_folio, 428 .readahead = blkdev_readahead, 429 .writepage = blkdev_writepage, 430 .write_begin = blkdev_write_begin, 431 .write_end = blkdev_write_end, 432 .direct_IO = blkdev_direct_IO, 433 .migrate_folio = buffer_migrate_folio_norefs, 434 .is_dirty_writeback = buffer_check_dirty_writeback, 435 }; 436 437 /* 438 * for a block special file file_inode(file)->i_size is zero 439 * so we compute the size by hand (just as in block_read/write above) 440 */ 441 static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence) 442 { 443 struct inode *bd_inode = bdev_file_inode(file); 444 loff_t retval; 445 446 inode_lock(bd_inode); 447 retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode)); 448 inode_unlock(bd_inode); 449 return retval; 450 } 451 452 static int blkdev_fsync(struct file *filp, loff_t start, loff_t end, 453 int datasync) 454 { 455 struct block_device *bdev = I_BDEV(filp->f_mapping->host); 456 int error; 457 458 error = file_write_and_wait_range(filp, start, end); 459 if (error) 460 return error; 461 462 /* 463 * There is no need to serialise calls to blkdev_issue_flush with 464 * i_mutex and doing so causes performance issues with concurrent 465 * O_SYNC writers to a block device. 466 */ 467 error = blkdev_issue_flush(bdev); 468 if (error == -EOPNOTSUPP) 469 error = 0; 470 471 return error; 472 } 473 474 blk_mode_t file_to_blk_mode(struct file *file) 475 { 476 blk_mode_t mode = 0; 477 478 if (file->f_mode & FMODE_READ) 479 mode |= BLK_OPEN_READ; 480 if (file->f_mode & FMODE_WRITE) 481 mode |= BLK_OPEN_WRITE; 482 if (file->private_data) 483 mode |= BLK_OPEN_EXCL; 484 if (file->f_flags & O_NDELAY) 485 mode |= BLK_OPEN_NDELAY; 486 487 /* 488 * If all bits in O_ACCMODE set (aka O_RDWR | O_WRONLY), the floppy 489 * driver has historically allowed ioctls as if the file was opened for 490 * writing, but does not allow and actual reads or writes. 491 */ 492 if ((file->f_flags & O_ACCMODE) == (O_RDWR | O_WRONLY)) 493 mode |= BLK_OPEN_WRITE_IOCTL; 494 495 return mode; 496 } 497 498 static int blkdev_open(struct inode *inode, struct file *filp) 499 { 500 struct block_device *bdev; 501 502 /* 503 * Preserve backwards compatibility and allow large file access 504 * even if userspace doesn't ask for it explicitly. Some mkfs 505 * binary needs it. We might want to drop this workaround 506 * during an unstable branch. 507 */ 508 filp->f_flags |= O_LARGEFILE; 509 filp->f_mode |= FMODE_BUF_RASYNC; 510 511 /* 512 * Use the file private data to store the holder for exclusive openes. 513 * file_to_blk_mode relies on it being present to set BLK_OPEN_EXCL. 514 */ 515 if (filp->f_flags & O_EXCL) 516 filp->private_data = filp; 517 518 bdev = blkdev_get_by_dev(inode->i_rdev, file_to_blk_mode(filp), 519 filp->private_data, NULL); 520 if (IS_ERR(bdev)) 521 return PTR_ERR(bdev); 522 523 if (bdev_nowait(bdev)) 524 filp->f_mode |= FMODE_NOWAIT; 525 526 filp->f_mapping = bdev->bd_inode->i_mapping; 527 filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping); 528 return 0; 529 } 530 531 static int blkdev_release(struct inode *inode, struct file *filp) 532 { 533 blkdev_put(I_BDEV(filp->f_mapping->host), filp->private_data); 534 return 0; 535 } 536 537 /* 538 * Write data to the block device. Only intended for the block device itself 539 * and the raw driver which basically is a fake block device. 540 * 541 * Does not take i_mutex for the write and thus is not for general purpose 542 * use. 543 */ 544 static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) 545 { 546 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); 547 struct inode *bd_inode = bdev->bd_inode; 548 loff_t size = bdev_nr_bytes(bdev); 549 size_t shorted = 0; 550 ssize_t ret; 551 552 if (bdev_read_only(bdev)) 553 return -EPERM; 554 555 if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev)) 556 return -ETXTBSY; 557 558 if (!iov_iter_count(from)) 559 return 0; 560 561 if (iocb->ki_pos >= size) 562 return -ENOSPC; 563 564 if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT) 565 return -EOPNOTSUPP; 566 567 size -= iocb->ki_pos; 568 if (iov_iter_count(from) > size) { 569 shorted = iov_iter_count(from) - size; 570 iov_iter_truncate(from, size); 571 } 572 573 ret = __generic_file_write_iter(iocb, from); 574 if (ret > 0) 575 ret = generic_write_sync(iocb, ret); 576 iov_iter_reexpand(from, iov_iter_count(from) + shorted); 577 return ret; 578 } 579 580 static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) 581 { 582 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); 583 loff_t size = bdev_nr_bytes(bdev); 584 loff_t pos = iocb->ki_pos; 585 size_t shorted = 0; 586 ssize_t ret = 0; 587 size_t count; 588 589 if (unlikely(pos + iov_iter_count(to) > size)) { 590 if (pos >= size) 591 return 0; 592 size -= pos; 593 shorted = iov_iter_count(to) - size; 594 iov_iter_truncate(to, size); 595 } 596 597 count = iov_iter_count(to); 598 if (!count) 599 goto reexpand; /* skip atime */ 600 601 if (iocb->ki_flags & IOCB_DIRECT) { 602 ret = kiocb_write_and_wait(iocb, count); 603 if (ret < 0) 604 goto reexpand; 605 file_accessed(iocb->ki_filp); 606 607 ret = blkdev_direct_IO(iocb, to); 608 if (ret >= 0) { 609 iocb->ki_pos += ret; 610 count -= ret; 611 } 612 iov_iter_revert(to, count - iov_iter_count(to)); 613 if (ret < 0 || !count) 614 goto reexpand; 615 } 616 617 ret = filemap_read(iocb, to, ret); 618 619 reexpand: 620 if (unlikely(shorted)) 621 iov_iter_reexpand(to, iov_iter_count(to) + shorted); 622 return ret; 623 } 624 625 #define BLKDEV_FALLOC_FL_SUPPORTED \ 626 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \ 627 FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE) 628 629 static long blkdev_fallocate(struct file *file, int mode, loff_t start, 630 loff_t len) 631 { 632 struct inode *inode = bdev_file_inode(file); 633 struct block_device *bdev = I_BDEV(inode); 634 loff_t end = start + len - 1; 635 loff_t isize; 636 int error; 637 638 /* Fail if we don't recognize the flags. */ 639 if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED) 640 return -EOPNOTSUPP; 641 642 /* Don't go off the end of the device. */ 643 isize = bdev_nr_bytes(bdev); 644 if (start >= isize) 645 return -EINVAL; 646 if (end >= isize) { 647 if (mode & FALLOC_FL_KEEP_SIZE) { 648 len = isize - start; 649 end = start + len - 1; 650 } else 651 return -EINVAL; 652 } 653 654 /* 655 * Don't allow IO that isn't aligned to logical block size. 656 */ 657 if ((start | len) & (bdev_logical_block_size(bdev) - 1)) 658 return -EINVAL; 659 660 filemap_invalidate_lock(inode->i_mapping); 661 662 /* Invalidate the page cache, including dirty pages. */ 663 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end); 664 if (error) 665 goto fail; 666 667 switch (mode) { 668 case FALLOC_FL_ZERO_RANGE: 669 case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE: 670 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT, 671 len >> SECTOR_SHIFT, GFP_KERNEL, 672 BLKDEV_ZERO_NOUNMAP); 673 break; 674 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE: 675 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT, 676 len >> SECTOR_SHIFT, GFP_KERNEL, 677 BLKDEV_ZERO_NOFALLBACK); 678 break; 679 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE | FALLOC_FL_NO_HIDE_STALE: 680 error = blkdev_issue_discard(bdev, start >> SECTOR_SHIFT, 681 len >> SECTOR_SHIFT, GFP_KERNEL); 682 break; 683 default: 684 error = -EOPNOTSUPP; 685 } 686 687 fail: 688 filemap_invalidate_unlock(inode->i_mapping); 689 return error; 690 } 691 692 static int blkdev_mmap(struct file *file, struct vm_area_struct *vma) 693 { 694 struct inode *bd_inode = bdev_file_inode(file); 695 696 if (bdev_read_only(I_BDEV(bd_inode))) 697 return generic_file_readonly_mmap(file, vma); 698 699 return generic_file_mmap(file, vma); 700 } 701 702 const struct file_operations def_blk_fops = { 703 .open = blkdev_open, 704 .release = blkdev_release, 705 .llseek = blkdev_llseek, 706 .read_iter = blkdev_read_iter, 707 .write_iter = blkdev_write_iter, 708 .iopoll = iocb_bio_iopoll, 709 .mmap = blkdev_mmap, 710 .fsync = blkdev_fsync, 711 .unlocked_ioctl = blkdev_ioctl, 712 #ifdef CONFIG_COMPAT 713 .compat_ioctl = compat_blkdev_ioctl, 714 #endif 715 .splice_read = filemap_splice_read, 716 .splice_write = iter_file_splice_write, 717 .fallocate = blkdev_fallocate, 718 }; 719 720 static __init int blkdev_init(void) 721 { 722 return bioset_init(&blkdev_dio_pool, 4, 723 offsetof(struct blkdev_dio, bio), 724 BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE); 725 } 726 module_init(blkdev_init); 727